U.S. patent number 9,290,584 [Application Number 13/176,082] was granted by the patent office on 2016-03-22 for polyalkylene carboxylic acid polyamine additives for fouling mitigation in hydrocarbon refining processes.
This patent grant is currently assigned to EXXONMOBIL RESEARCH AND ENGINEERING COMPANY. The grantee listed for this patent is Patrick Brant, Glen B. Brons, Hong Cheng, Donna J. Crowther, David T. Ferrughelli, John R. Hagadorn, Kevin Mallory, Man Kit Ng, Emmanuel Ulysse. Invention is credited to Patrick Brant, Glen B. Brons, Hong Cheng, Donna J. Crowther, David T. Ferrughelli, John R. Hagadorn, Kevin Mallory, Man Kit Ng, Emmanuel Ulysse.
United States Patent |
9,290,584 |
Ng , et al. |
March 22, 2016 |
Polyalkylene carboxylic acid polyamine additives for fouling
mitigation in hydrocarbon refining processes
Abstract
Methods and systems for reducing fouling, including
particulate-induced fouling, in a hydrocarbon refining process
including the steps of providing a crude hydrocarbon for a refining
process and adding an antifouling agent containing a polymer base
unit and a polyamine group to the crude hydrocarbon are provided.
The antifouling agent can be obtained by converting a vinyl
terminated polymer, such as polypropylene or
poly(ethylene-co-propylene), to a terminal acyl containing
functional group, followed by reacting the terminal acyl containing
functional group with a polyamine compound.
Inventors: |
Ng; Man Kit (Annandale, NJ),
Brons; Glen B. (Phillipsburg, NJ), Ferrughelli; David T.
(Flemington, NJ), Cheng; Hong (Bridgewater, NJ), Mallory;
Kevin (Clinton, NJ), Ulysse; Emmanuel (Maplewood,
NJ), Hagadorn; John R. (Houston, TX), Crowther; Donna
J. (Seabrook, TX), Brant; Patrick (Seabrook, TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
Ng; Man Kit
Brons; Glen B.
Ferrughelli; David T.
Cheng; Hong
Mallory; Kevin
Ulysse; Emmanuel
Hagadorn; John R.
Crowther; Donna J.
Brant; Patrick |
Annandale
Phillipsburg
Flemington
Bridgewater
Clinton
Maplewood
Houston
Seabrook
Seabrook |
NJ
NJ
NJ
NJ
NJ
NJ
TX
TX
TX |
US
US
US
US
US
US
US
US
US |
|
|
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY (Annandale, NJ)
|
Family
ID: |
46545896 |
Appl.
No.: |
13/176,082 |
Filed: |
July 5, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130008830 A1 |
Jan 10, 2013 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10L
1/2383 (20130101); C08F 8/04 (20130101); C10L
1/224 (20130101); C10L 10/00 (20130101); C10G
75/04 (20130101); C08F 8/32 (20130101); C08F
8/32 (20130101); C08F 10/06 (20130101); C08F
8/04 (20130101); C08F 10/06 (20130101) |
Current International
Class: |
C10G
29/20 (20060101); C08F 8/04 (20060101); C10G
75/04 (20060101); C10L 1/2383 (20060101); C10L
1/224 (20060101); C10L 10/00 (20060101); C08F
8/32 (20060101) |
Field of
Search: |
;208/289,48AA
;564/123,133-144,192-197,204 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
1283239 |
|
Feb 2003 |
|
EP |
|
2009155471 |
|
Dec 2009 |
|
WO |
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2009155472 |
|
Dec 2009 |
|
WO |
|
Other References
PCT International Search Report issued Sep. 14, 2012 in
corresponding PCT Application No. PCT/US2012/044492, 3 pgs. cited
by applicant .
PCT Written Opinion issued Sep. 14, 2012 in corresponding PCT
Application No. PCT/US2012/044492, 6 pgs. cited by
applicant.
|
Primary Examiner: Singh; Prem C
Assistant Examiner: Doyle; Brandi M
Attorney, Agent or Firm: Barrett; Glenn T. Ward; Andrew
T.
Claims
The invention claimed is:
1. A method for reducing fouling in a hydrocarbon refining process
comprising providing a crude hydrocarbon for a refining process;
adding an additive to the crude hydrocarbon, the additive
represented by the formula: ##STR00018## wherein R.sub.1 is a
branched or straight-chained C.sub.64-C.sub.342 alkyl or alkenyl
group; R.sub.2 is ##STR00019## wherein the carbonyl carbon connects
to nitrogen, the bond between carbons C.sub.p and C.sub.q is either
a single or double bond, wherein when the bond between carbons
C.sub.p and C.sub.q is a single bond, a hydrogen is attached to
each of C.sub.p and C.sub.q as required by valency; R' and R'' are
independently H or unsubstituted or substituted C.sub.1-C.sub.4
alkyl or C.sub.1-C.sub.4 alkenyl, and Z is a bond or unsubstituted
or substituted C.sub.1-C.sub.4 alkylene; R.sub.3 is a
C.sub.1-C.sub.10 branched or straight chained alkylene group; n is
an integer from 1 to 10; R.sub.4 and R.sub.5 are both independently
selected from hydrogen and --R.sub.6-R.sub.7, wherein R.sub.6 is
defined the same as R.sub.2 above, and R.sub.7 is a
C.sub.64-C.sub.342 branched or straight chained alkyl or alkenyl
group, or one of R.sub.4 and R.sub.5 is absent as required by
valency and the other of R.sub.4 and R.sub.5 is hydrogen or
--R.sub.6-R.sub.7 as defined above; R.sub.31 is hydrogen or
--R.sub.8-R.sub.9, wherein R.sub.8 is defined the same as R.sub.2
above, and R.sub.9 is branched or straight-chained
C.sub.64-C.sub.342 alkyl or alkenyl group, or R.sub.8 and R.sub.9
together are a C.sub.1-C.sub.10 branched or straight chained alkyl
group optionally substituted with one or more amine groups; and
wherein the --N(R.sub.31)--R.sub.3-- repeat unit is optionally
interrupted in one or more places by a heterocyclic or homocyclic
cycloalkyl group.
2. The method of claim 1, wherein at least one of R.sub.1, R.sub.7,
and R.sub.9 comprises polypropylene.
3. The method of claim 2, wherein the polypropylene is atactic
polypropylene, isotactic polypropylene, or syndiotactic
polypropylene.
4. The method of claim 2, wherein the polypropylene is
amorphous.
5. The method of claim 2, wherein the polypropylene include
isotactic or syndiotactic crystallizable units.
6. The method of claim 2, wherein the polypropylene include meso
diads constituting from about 30% to about 99.5% of the total diads
of the polypropylene.
7. The method of claim 2, wherein at least one of R.sub.1, R.sub.7,
and R.sub.9 has a number-averaged molecular weight of from about
300 to about 30000 g/mol.
8. The method of claim 2, wherein at least one of R.sub.1, R.sub.7,
and R.sub.9 has a number-averaged molecular weight of from about
500 to about 5000 g/mol.
9. The method of claim 1, wherein at least one of R.sub.1, R.sub.7,
and R.sub.9 comprises polyethylene.
10. The method of claim 1, wherein at least one of R.sub.1,
R.sub.7, and R.sub.9 comprises poly(ethylene-co-propylene).
11. The method of claim 10, wherein at least one of R.sub.1,
R.sub.7, and R.sub.9 comprises from about 1 mole % to about 90 mole
% of ethylene units and from about 99 mole % to about 10 mole %
propylene units.
12. The method of claim 11, wherein at least one of R.sub.1,
R.sub.7, and R.sub.9 comprises from about 10 mole % to about 50
mole % of ethylene units.
13. The method of claim 1, wherein R.sub.1 is
poly(ethylene-co-propylene), R.sub.3 is --CH.sub.2CH.sub.2--,
R.sub.31 is hydrogen, and R.sub.4 and R.sub.5 are both
hydrogen.
14. The method of claim 1, wherein R.sub.2 is
--CH.sub.2--CH.sub.2--C(O)--.
15. The method of claim 1, wherein the nitrogen content in the
additive is about wt % to about 10 wt % based on the total weight
of the additive.
16. A method for reducing fouling in a hydrocarbon refining process
comprising providing a crude hydrocarbon for a refining process;
adding an additive to the crude hydrocarbon, the additive being a
reaction product of (a) a polymer base unit R.sub.11, which is a
branched or straight-chained C.sub.64-C.sub.342 alkyl or alkenyl
group having a vinyl terminal group; (b) an acrylic compound
represented by H.sub.2C.dbd.CH--C(O)--Y, wherein Y is a functional
group selected from halogen, --R*, --OR*, --SR*, --NR*R**, where R*
and R** are both independently selected from hydrogen and
substituted or unsubstituted C.sub.1-C.sub.10 alkyl or
C.sub.1-C.sub.10 alkenyl, and wherein a hydrogen connecting to
either of the carbons forming the double bond may be optionally
replaced by a C.sub.1-C.sub.4 alkyl; (c) optionally, hydrogen; (d)
a polyamine represented by the formula: ##STR00020## wherein
R.sub.12 is hydrogen or a C.sub.1-C.sub.10 branched or straight
chained alkyl optionally substituted with one or more amine groups,
R.sub.13 is a C.sub.1-C.sub.10 branched or straight chained
alkylene group, and x is an integer between 1 and 10, wherein the
--N(R.sub.12)--R.sub.13-- unit is optionally interrupted in one or
more places by a heterocyclic or homocyclic cycloalkyl group, and
wherein when the --N(R.sub.12)--R.sub.13-- unit along with the
terminal nitrogen atom forms a heterocyclic cycloalkyl group at the
right terminal end, the terminal --NH.sub.2 is replaced by a --NH--
group as required by valency.
17. The method of claim 16, wherein the polyamine is selected from
ethylenediamine, diethylenetriamine, triethylenetetramine,
tetraethylenepentamine, pentaethylenehexamine, and
hexaethyleneheptamine.
18. The method of claim 16, wherein the polyamine is a heavy
polyamine.
19. The method of claim 16, wherein R.sub.11 comprises
polypropylene.
20. The method of claim 16, wherein the molar ratio of
R.sub.11:polyamine ranges from about 5:1 to about 1:1.
21. The method of claim 19, wherein R.sub.11 has a number-averaged
molecular weight of from about 300 to about 30000 g/mol.
22. The method of claim 21, wherein R.sub.11 has a number-averaged
molecular weight of from about 500 to about 5000 g/mol.
23. The method of claim 19, wherein the polypropylene is atactic
polypropylene, isotactic polypropylene, or syndiotactic
polypropylene.
24. The method of claim 19, wherein the polypropylene is
amorphous.
25. The method of claim 19, wherein the polypropylene include
isotactic or syndiotactic crystallizable units.
26. The method of claim 19, wherein the polypropylene include meso
diads constituting from about 30% to about 99.5% of the total diads
of the polypropylene.
27. The method f claim 16, wherein R.sub.11 comprises
polyethylene.
28. The method of claim 16, wherein R.sub.11 comprises
poly(ethylene-co-propylene).
29. The method of claim 28, wherein R.sub.11 comprises from about
10 mole % to about 90 mole % of ethylene units and from about 90
mole % to about 10 mole % propylene units.
30. The method of claim 29, wherein R.sub.11 comprises from about
20 mole % to about 50 mole % of ethylene units.
31. The method of claim 29, wherein the acrylic compound is acrylic
acid or methacrylic acid.
32. The method of claim 16, wherein acrylic compound in (a) is a
(C.sub.1-C.sub.4) acrylate or a (C.sub.1-C.sub.4)alkyl
methacrylate.
33. The method of claim 32, wherein the acrylic compound in (a) is
selected from methyl acrylate, methyl methacrylate, ethyl acrylate,
and ethyl methacrylate.
34. The method of claim 16, wherein at least 50% of the terminal
vinyl groups of R.sub.11 are an allylic vinyl group.
Description
FIELD OF THE INVENTION
The presently disclosed subject matter relates to additives to
reduce fouling of crude hydrocarbon refinery components, and
methods and systems using the same.
BACKGROUND OF THE INVENTION
Petroleum refineries incur additional energy costs, perhaps
billions per year, due to fouling and the resulting attendant
inefficiencies caused by the fouling. More particularly, thermal
processing of crude oils, blends and fractions in heat transfer
equipment, such as heat exchangers, is hampered by the deposition
of insoluble asphaltenes and other contaminants (i.e.,
particulates, salts, etc.) that may be found in crude oils.
Further, the asphaltenes and other organics are known to thermally
degrade to coke when exposed to high heater tube surface
temperatures.
Fouling in heat exchangers receiving petroleum-type process streams
can result from a number of mechanisms including chemical
reactions, corrosion, deposit of existing insoluble impurities in
the stream, and deposit of materials rendered insoluble by the
temperature difference (.DELTA.T) between the process stream and
the heat exchanger wall. For example, naturally-occurring
asphaltenes can precipitate from the crude oil process stream,
thermally degrade to form a coke and adhere to the hot surfaces.
Further, the high .DELTA.T found in heat transfer operations result
in high surface or skin temperatures when the process stream is
introduced to the heater tube surfaces, which contributes to the
precipitation of insoluble particulates. Another common cause of
fouling is attributable to the presence of salts, particulates and
impurities (e.g., inorganic contaminants) found in the crude oil
stream. For example, iron oxide/sulfide, calcium carbonate, silica,
sodium chloride and calcium chloride have all been found to attach
directly to the surface of a fouled heater rod and throughout the
coke deposit. These solids promote and/or enable additional fouling
of crude oils.
The buildup of insoluble deposits in heat transfer equipment
creates an unwanted insulating effect and reduces the heat transfer
efficiency. Fouling also reduces the cross-sectional area of
process equipment, which decreases flow rates and desired pressure
differentials. To overcome these disadvantages, heat transfer
equipment are ordinarily taken offline and cleaned mechanically or
chemically cleaned, resulting in lost production time.
Accordingly, there is a need to reduce precipitation/adherence of
particulates and asphaltenes from the heated surface to prevent
fouling, and before the asphaltenes are thermally degraded or
coked. This will improve the performance of the heat transfer
equipment, decrease or eliminate scheduled outages for fouling
mitigation efforts, and reduce energy costs associated with the
processing activity.
SUMMARY OF THE INVENTION
In accordance with one aspect of the presently disclosed subject
matter, a method for reducing fouling in a hydrocarbon refining
process is provided. The method includes providing a crude
hydrocarbon for a refining process, and adding an additive to the
crude hydrocarbon, the additive being represented by:
##STR00001##
wherein R.sub.1 is a branched or straight-chained
C.sub.10-C.sub.800 alkyl or alkenyl group;
R.sub.2 is
##STR00002## wherein the carbonyl carbon connects to nitrogen, the
bond between carbons C.sub.p and C.sub.q can be either single or
double bond, wherein when the bond between carbons C.sub.p and
C.sub.q is a single bond, a hydrogen is attached to each of C.sub.p
and C.sub.q as required by valency; R' and R'' are independently H
or unsubstituted or substituted C.sub.1-C.sub.4 alkyl or
C.sub.1-C.sub.4 alkenyl, and Z is a bond or unsubstituted or
substituted C.sub.1-C.sub.4 alkylene;
R.sub.3 is a C.sub.1-C.sub.10 branched or straight chained alkylene
group;
n is an integer from 1 to 10;
R.sub.4 and R.sub.5 are both independently selected from the group
consisting of hydrogen and --R.sub.6-R.sub.7, wherein R.sub.6 is
defined the same as R.sub.2 above, and R.sub.7 is a
C.sub.10-C.sub.800 branched or straight chained alkyl or alkenyl
group, or one of R.sub.4 and R.sub.5 is absent as required by
valency and the other of R.sub.4 and R.sub.5 is hydrogen or
--R.sub.6-R.sub.7 as defined above;
R.sub.31 is hydrogen or --R.sub.8-R.sub.9, wherein R.sub.8 is
defined the same as R.sub.2 above, and R.sub.9 is branched or
straight-chained C.sub.10-C.sub.800 alkyl or alkenyl group, or
R.sub.8 and R.sub.9 together are a C.sub.1-C.sub.10 branched or
straight chained alkyl group optionally substituted with one or
more amine groups;
and wherein the --N(R.sub.31)--R.sub.3-- repeat unit is optionally
interrupted in one or more places by a heterocyclic or homocyclic
cycloalkyl group.
According to another aspect of the presently disclosed subject
matter, a method for reducing fouling in a hydrocarbon refining
process is provided. The method includes providing a crude
hydrocarbon for a refining process, and adding an additive to the
crude hydrocarbon, the additive being a reaction product of
(a) a polymer base unit R.sub.11, which is a branched or
straight-chained C.sub.10-C.sub.800 alkyl or alkenyl group having a
vinyl terminal group;
(b) an acrylic compound represented by H.sub.2C.dbd.CH--C(O)--Y,
wherein Y is a functional group selected from halogen, --R*, --OR*,
--SR*, --NR*R**, where R* and R** are both independently selected
from hydrogen and substituted or unsubstituted C.sub.1-C.sub.10
alkyl or C.sub.1-C.sub.10 alkenyl, and wherein a hydrogen
connecting to either of the carbons forming the double bond may be
optionally replaced by a C.sub.1-C.sub.4 alkyl;
(c) optionally, hydrogen; and
(d) a polyamine represented by the formula:
##STR00003## wherein R.sub.12 is hydrogen or a C.sub.1-C.sub.10
branched or straight chained alkyl optionally substituted with one
or more amine groups, R.sub.13 is a C.sub.1-C.sub.10 branched or
straight chained alkylene group, and x is an integer between 1 and
10, wherein the --N(R.sub.12)--R.sub.13-- unit is optionally
interrupted in one or more places by a heterocyclic or homocyclic
cycloalkyl group, and wherein when the --N(R.sub.12)--R.sub.13--
unit along with the terminal nitrogen atom forms a heterocyclic
cycloalkyl group at the right terminal end, the terminal --NH.sub.2
is replaced by a --NH-- group as required by valency.
According to yet another aspect of the presently disclosed subject
matter, a method for preparing an antifoulant useful for reducing
fouling in a hydrocarbon refining process is provided. The method
includes:
(a) reacting a polymer base unit R.sub.11, which is a branched or
straight-chained C.sub.10-C.sub.800 alkyl or alkenyl group having a
vinyl terminal group, with an acrylic compound represented by
H.sub.2C.dbd.CH--C(O)--Y, wherein Y is a functional group selected
from halogen, --R*, --OR*, --SR*, --NR*R**, wherein R* and R** are
both independently selected from hydrogen and substituted or
unsubstituted C.sub.1-C.sub.10 alkyl or C.sub.1-C.sub.10 alkenyl,
and wherein a hydrogen connecting to either of the carbons forming
the double bond may be optionally replaced by a C.sub.1-C.sub.4
alkyl; wherein the reaction between R.sub.11 and the acrylic
compound is a cross-metathesis reaction;
(b) optionally, hydrogenating the compound formed in (a);
(c) reacting the compound formed in (a) or (b) with a polyamine
represented by
##STR00004## wherein R.sub.12 is hydrogen or a C.sub.1-C.sub.10
branched or straight chained alkyl optionally substituted with one
or more amine groups, R.sub.13 is a C.sub.1-C.sub.10 branched or
straight chained alkylene group, and x is an integer between 1 and
10, wherein the --N(R.sub.12)--R.sub.13-- unit is optionally
interrupted in one or more places by a heterocyclic or homocyclic
cycloalkyl group, and wherein when the --N(R.sub.12)--R.sub.13--
unit along with the terminal nitrogen atom forms a heterocyclic
cycloalkyl group at the right terminal end, the terminal --NH.sub.2
is replaced by a --NH-- group as required by valency.
In addition, the presently disclosed subject matter provides the
additives as described in the above methods, antifouling
compositions including such additives, and systems for refining
hydrocarbons containing such additives and compositions.
BRIEF DESCRIPTION OF THE DRAWINGS
The presently disclosed subject matter will now be described in
conjunction with the accompanying drawings in which:
FIG. 1 is a schematic view of a representative embodiment of an oil
refinery crude pre-heat train, annotated to show non-limiting
injection points for the additives of the presently disclosed
subject matter.
FIG. 2 is a schematic of the Alcor Hot Liquid Process Simulator
(HLPS) employed in Example 2 of the present application.
FIG. 3 is a graph demonstrating the effects of fouling of a control
crude oil blend sample and the crude oil blend sample treated with
50 wppm of a polypropylene carboxylic acid polyamine (PP-CA-PAM)
additive, as measured by the Alcor HLPS apparatus depicted in FIG.
2.
FIG. 4 is a graph demonstrating the effects of fouling of a control
crude oil blend sample and the crude oil blend sample treated with
50 wppm of another polypropylene carboxylic acid polyamine
(PP-CA-PAM) additive, as measured by the Alcor HLPS apparatus
depicted in FIG. 2.
DETAILED DESCRIPTION
Definitions
The following definitions are provided for purpose of illustration
and not limitation.
As used herein, the term "fouling" generally refers to the
accumulation of unwanted materials on the surfaces of processing
equipment or the like, particularly processing equipment in a
hydrocarbon refining process.
As used herein, the term "particulate-induced fouling" generally
refers to fouling caused primarily by the presence of variable
amounts of organic or inorganic particulates. Organic particulates
(such as precipitated asphaltenes and coke particles) include, but
are not limited to, insoluble matter precipitated out of solution
upon changes in process conditions (e.g., temperature, pressure, or
concentration changes) or a change in the composition of the feed
stream (e.g., changes due to the occurrence of a chemical
reaction). Inorganic particulates include, but are not limited to,
silica, iron oxide, iron sulfide, alkaline earth metal oxide,
sodium chloride, calcium chloride and other inorganic salts. One
major source of these particulates results from incomplete solids
removal during desalting and/or other particulate removing
processes. Solids promote the fouling of crude oils and blends due
to physical effects by modifying the surface area of heat transfer
equipment, allowing for longer holdup times at wall temperatures
and causing coke formation from asphaltenes and/or crude
oil(s).
As used herein, the term "alkyl" refers to a monovalent hydrocarbon
group containing no double or triple bonds and arranged in a
branched or straight chain.
As used herein, the term "alkylene" refers to a divalent
hydrocarbon group containing no double or triple bonds and arranged
in a branched or straight chain.
As used herein, the term "alkenyl" refers to a monovalent
hydrocarbon group containing one or more double bonds and arranged
in a branched or straight chain.
As used herein, a "hydrocarbyl" group refers to any univalent
radical that is derived from a hydrocarbon, including univalent
alkyl, aryl and cycloalkyl groups.
As used herein, "carboxylic acid amine" refers to a chemical
structure where an acyl group is connected to an amine via a
carbon-nitrogen bond.
As used herein, the term "crude hydrocarbon refinery component"
generally refers to an apparatus or instrumentality of a process to
refine crude hydrocarbons, such as an oil refinery process, which
is, or can be, susceptible to fouling. Crude hydrocarbon refinery
components include, but are not limited to, heat transfer
components such as a heat exchanger, a furnace, a crude preheater,
a coker preheater, or any other heaters, a FCC slurry bottom, a
debutanizer exchanger/tower, other feed/effluent exchangers and
furnace air preheaters in refinery facilities, flare compressor
components in refinery facilities and steam cracker/reformer tubes
in petrochemical facilities. Crude hydrocarbon refinery components
can also include other instrumentalities in which heat transfer can
take place, such as a fractionation or distillation column, a
scrubber, a reactor, a liquid-jacketed tank, a pipestill, a coker
and a visbreaker. It is understood that "crude hydrocarbon refinery
components," as used herein, encompasses tubes, piping, baffles and
other process transport mechanisms that are internal to, at least
partially constitute, and/or are in direct fluid communication
with, any one of the above-mentioned crude hydrocarbon refinery
components.
As used herein, a reduction (or "reducing") particulate-induced
fouling is generally achieved when the ability of particulates to
adhere to heated equipment surfaces is reduced, thereby mitigating
their impact on the promotion of the fouling of crude oil(s),
blends, and other refinery process streams.
As used herein, reference to a group being a particular polymer
(e.g., polypropylene or poly(ethylene-co-propylene) encompasses
polymers that contain primarily the respective monomer along with
negligible amounts of other substitutions and/or interruptions
along polymer chain. In other words, reference to a group being a
polypropylene group does not require that the group consist of 100%
propylene monomers without any linking groups, substitutions,
impurities or other substituents (e.g., alkylene or alkenylene
substituents). Such impurities or other substituents can be present
in relatively minor amounts so long as they do not significantly
affect the industrial performance of the additive, as compared to
the same additive containing the respective polymer substituent
with 100% purity.
For the purposes of the presently disclosed subject matter and the
claims thereto when a polymer is referred to as comprising or
including an olefin, the olefin present in the polymer is the
polymerized form of the olefin.
As used herein, a copolymer is a polymer comprising at least two
different monomer units (such as propylene and ethylene). A
homo-polymer is a polymer comprising units of the same monomer
(such as propylene).
The term "vinyl termination", also referred to as "allyl chain
end(s)" or "vinyl content" refers to a polymer having at least one
terminus represented by formula:
##STR00005## where the "" represents the polymer chain.
In one embodiment, the allyl chain end is represented by the
formula:
##STR00006##
The amount of allyl chain ends (also called % vinyl termination)
can be determined using .sup.1H NMR at 120.degree. C. using
deuterated tetrachloroethane as the solvent on a 500 MHz machine
and can be confirmed by .sup.13C NMR. Resconi has reported proton
and carbon assignments for vinyl terminated propylene polymers in
J. Am. Chem. Soc. 1992, 114, 1025-1032. Janiak has also described
.sup.1H NMR assignments for polypropylenes with allylic end group
in Coordination Chemistry Reviews 2006, vol. 250, pp. 66-94, hereby
incorporated by reference in its entirety, which are useful for the
presently disclosed subject matter.
"Isobutyl chain end" is defined to be a polymer having at least one
terminus represented by the formula:
##STR00007## where M represents the polymer chain. In one
embodiment, the isobutyl chain end is represented by one of the
following formulae:
##STR00008## where M represents the polymer chain.
The percentage of isobutyl end groups is determined using .sup.13C
NMR (as described in the example section of U.S. patent application
Ser. No. 12/488,066, filed Jun. 19, 2009, and published as
US20090318640) and the chemical shift assignments in Resconi et al,
J. Am. Chem. Soc. 1992, 114, 1025-1032 for 100% propylene polymers
and set forth in FIG. 2 for E-P polymers, the disclosure of each of
which is incorporated by reference in its entirety.
The "isobutyl chain end to allylic vinyl group ratio" is defined to
be the ratio of the percentage of isobutyl chain ends to the
percentage of allylic vinyl groups.
A reaction zone is any vessel where a reaction occurs, such as
glass vial, a polymerization reactor, reactive extruder, tubular
reactor and the like.
As used herein, the term "polymer" refers to a chain of monomers
having a Mn of at least 80 g/mol, preferably greater than 100 g/mol
and more preferably greater than 120 g/mol.
Reference will now be made to various aspects of the presently
disclosed subject matter in view of the definitions above.
The techniques provided herein are based, at least in part, on
interactions between the antifouling additives according to the
presently disclosed subject matter and the materials in crude oils
that are prone to cause fouling, e.g., particulate
impurities/contaminants and asphaltenes. The interaction can be of
physical or chemical means such as, but not limited to, absorption,
association, or chemical bonding. The fouling materials can be
rendered more soluble in the crude oils as a result of interaction
with the antifouling additives, therefore the fouling on the
exchanger metal surfaces can be reduced or eliminated.
The systems, methods and compounds of the presently disclosed
subject matter are described below in conjunction with each other.
For example, the various embodiments directed to the antifoulant
compounds, may they be described structurally or products of
processes, should be understood as applicable for the disclosed
methods and the systems for reducing fouling.
In accordance with one aspect of the presently disclosed subject
matter, a method is provided for reducing fouling. The method
includes providing a crude hydrocarbon for a refining process, and
adding to the crude hydrocarbon one or more additives (also
referred to as antifouling agent or antifoulant) selected from:
##STR00009##
wherein R.sub.1 is a branched or straight-chained
C.sub.10-C.sub.800 alkyl or alkenyl group;
R.sub.2 is
##STR00010## wherein the carbonyl carbon connects to nitrogen, the
bond between carbons C.sub.p and C.sub.q can be either single or
double bond, wherein when the bond between carbons C.sub.p and
C.sub.q is a single bond, a hydrogen is attached to each of C.sub.p
and C.sub.q as required by valency; R' and R'' are independently H
or unsubstituted or substituted C.sub.1-C.sub.4 alkyl or
C.sub.1-C.sub.4 alkenyl and Z is a bond or unsubstituted or
substituted C.sub.1-C.sub.4 alkylene;
R.sub.3 is a C.sub.1-C.sub.10 branched or straight chained alkylene
group;
n is an integer from 1 to 10;
R.sub.4 and R.sub.5 are both independently selected from the group
consisting of hydrogen and --R.sub.6-R.sub.7, wherein R.sub.6 is
defined the same as R.sub.2 above, and R.sub.7 is a
C.sub.10-C.sub.800 branched or straight chained alkyl or alkenyl
group, or one of R.sub.4 and R.sub.5 is absent as required by
valency and the other of R.sub.4 and R.sub.5 is hydrogen or
--R.sub.6-R.sub.7 as defined above;
R.sub.31 is hydrogen or --R.sub.8-R.sub.9, wherein R.sub.8 is
defined the same as R.sub.2 above, and R.sub.9 is branched or
straight-chained C.sub.10-C.sub.800 alkyl or alkenyl group, or
R.sub.8 and R.sub.9 together are a C.sub.1-C.sub.10 branched or
straight chained alkyl group optionally substituted with one or
more amine groups;
and wherein the --N(R.sub.31)--R.sub.3-- repeat unit is optionally
interrupted in one or more places by a heterocyclic or homocyclic
cycloalkyl group.
In certain embodiments, at least one of R.sub.1, R.sub.7, and
R.sub.9 of Formula I includes polypropylene (PP). The polypropylene
can be amorphous polypropylene or polypropylene comprising
crystallizable units. For example, the polypropylene can be
atactic, syndiotactic, or isotactic. The polypropylene can also
include units or portions that are syndiotactic, and/or units or
portions that are isotactic. In one embodiment, the meso diads in
the polypropylene constitute from about 30% to about 99.5% of the
total diads of the polypropylene. In an alternative embodiment, at
least one of R.sub.1, R.sub.7, and R.sub.9 of the additive of
Formula I includes polyethylene (PE).
In a further embodiment, at least one of R.sub.1, R.sub.7, and
R.sub.9 of the additive of Formula I includes
poly(ethylene-co-propylene) (EP). The mole percentage of the
ethylene units and propylene units in the
poly(ethylene-co-propylene) can vary. For example, in some
embodiments, the poly(ethylene-co-propylene) can contain about 1 to
about 90 mole % of ethylene units and about 99 mole % to about 10
mole % propylene units. In other embodiments, the
poly(ethylene-co-propylene) can contain about 10 mole % to about 90
mole % of ethylene units and about 90 mole % to about 10 mole %
propylene units. In certain embodiments, the
poly(ethylene-co-propylene) contains about 20 mole % to about 50
mole % of ethylene units.
In some embodiments of the above method, at least one of R.sub.1,
R.sub.7, and R.sub.9 of the additive of Formula I has a
number-averaged molecular weight of from about 300 to about 30,000
g/mol (assuming one olefin unsaturation per chain, as measured by
.sup.1H NMR). Alternatively, at least one of R.sub.1, R.sub.7, and
R.sub.9 of the additive of Formula I has a number-averaged
molecular weight of from about 500 to about 5,000 g/mol. In one
embodiment, the PP or EP included in the R.sub.1, R.sub.7 or
R.sub.9 of the additive Formula I, individually, have a molecular
weight from about 300 to about 30,000 g/mol, or from about 500 to
about 5000 g/mol. In one embodiment, the PP or EP groups have a
molecular weight, individually, ranging from about 500 to about
2500 g/mol, or a molecular weight of from about 500 to about 650
g/mol, or a molecular weight of from about 800 to about 1000 g/mol,
or a molecular weight of from about 1000 to about 1500 g/mol, or a
molecular weight of from about 1500 to about 2000 g/mol, or a
molecular weight of from about 2000 to about 2500 g/mol.
In particular embodiments, in the additive of Formula I in the
above method, R.sub.1 is poly(ethylene-co-propylene), R.sub.3 is
--CH.sub.2CH.sub.2--, R.sub.31 is hydrogen, and R.sub.4 and R.sub.5
are both hydrogen. In one embodiment, R.sub.2 is
--CH.sub.2--CH.sub.2--C(O)--.
In certain embodiments of the above method, the nitrogen content in
the additive of Formula I is about 1 wt % to about 10 wt % based on
the total weight of the additive.
In accordance with another aspect of the presently disclosed
subject matter, a method is provided for reducing fouling. The
method includes providing a crude hydrocarbon for a refining
process, and adding to the crude hydrocarbon one or more additives
which are a reaction product of
(a) a polymer base unit R.sub.11, which is a branched or
straight-chained C.sub.10-C.sub.800 alkyl or alkenyl group having a
vinyl terminal group;
(b) an acrylic compound represented by H.sub.2C.dbd.CH--C(O)--Y,
wherein Y is a functional group selected from halogen, --R*, --OR*,
--SR*, --NR*R**, where R* and R** are both independently selected
from hydrogen and substituted or unsubstituted C.sub.1-C.sub.10
alkyl or C.sub.1-C.sub.10 alkenyl, and wherein a hydrogen
connecting to either of the carbons forming the double bond may be
optionally replaced by a C.sub.1-C.sub.4 alkyl;
(c) optionally, hydrogen; and
(d) a polyamine represented by the formula:
##STR00011## wherein R.sub.12 is hydrogen or a C.sub.1-C.sub.10
branched or straight chained alkyl optionally substituted with one
or more amine groups, R.sub.13 is a C.sub.1-C.sub.10 branched or
straight chained alkylene group, and x is an integer between 1 and
10, wherein the --N(R.sub.12)--R.sub.13-- unit is optionally
interrupted in one or more places by a heterocyclic or homocyclic
cycloalkyl group, and wherein when the --N(R.sub.12)--R.sub.13--
unit along with the terminal nitrogen atom forms a heterocyclic
cycloalkyl group at the right terminal end, the terminal --NH.sub.2
is replaced by a --NH-- group as required by valency.
In certain embodiments of the above method, the polymer base unit
R.sub.11 has a number-averaged molecular weight of 300 to 30,000
g/mol (assuming one olefin unsaturation per chain, as measured by
.sup.1H NMR), and alternatively, about 500 to 5,000 g/mol.
In some embodiments of the above method, the polymer base unit
R.sub.11 includes polypropylene. The polypropylene can be amorphous
polypropylene or polypropylene comprising crystallizable units. For
example, the polypropylene can be atactic, syndiotactic, or
isotactic. The polypropylene can also include units or portions
that are syndiotactic, and/or units or portions that are isotactic.
In one embodiment, the meso diads in the polypropylene constitute
from about 30% to about 99.5% of the total diads of the
polypropylene. The polymer base unit R.sub.11 can also include
polyethylene.
In alternative embodiments, the polymer base unit R.sub.11 includes
poly(ethylene-co-propylene). The poly(ethylene-co-propylene) can
contain from about 1 or 10 mole % to about 99 or 90 mole % of
ethylene units and from about 99 or 90 mole % to about 1 or 10 mole
% propylene units. In one embodiment, the
poly(ethylene-co-propylene) polymer contains from about 2 or 20
mole % to about 50 mole % ethylene units.
In one embodiment, the PP or EP included in the R.sub.11 of the
additive Formula I, individually, have a number-averaged molecular
weight (M.sub.n) molecular weight from about 300 to about 30,000
g/mol, or from about 500 to about 5000 g/mol (assuming one olefin
unsaturation per chain, as measured by .sup.1H NMR). In one
embodiment, the PP or EP groups have a molecular weight,
individually, ranging from about 500 to about 2500 g/mol, or a
molecular of from about 500 to about 650 g/mol, or a molecular
weight of from about 800 to about 1000 g/mol, or a molecular weight
of from about 1000 to about 1500 g/mol, or a molecular weight of
from about 1500 to about 2000 g/mol, or a molecular weight of from
about 2000 to about 2500 g/mol.
In embodiments where the polymer base unit R.sub.11, include
polypropylene or poly(ethylene-co-propylene), such groups can be
prepared, for example, by metallocene-catalyzed polymerization of
propylene or a mixture of ethylene and propylene, which are then
terminated with a high vinyl group content in the chain end. The
number-averaged molecular weight (M.sub.n) of the PP or EP can be
from about 300 to about 30,000 g/mol, as determined by .sup.1H NMR
spectroscopy. The vinyl-terminated polypropylenes (v-PP) or
vinyl-terminated poly(ethylene-co-propylene) (v-EP) suitable for
further chemical functionalization can have a molecular weight
(M.sub.n) approximately from about 300 to about 30,000 g/mol, or
about 500 to 5,000 g/mol. The terminal olefin group can be a
vinylidene group or an allylic vinyl group. In certain embodiments,
the terminal olefin group is an allylic vinyl group.
In another embodiment, one or more of the R.sub.1, R.sub.7 and
R.sub.9 groups is independently selected from propylene polymers
comprising propylene and less than 1.0 wt % comonomer, for example,
0 wt % comonomer, wherein the polymer has: i) at least 70% allyl
chain ends, preferably at least 75% allyl chain ends, more
preferably at least 80% allyl chain ends, even more preferably at
least 90% allyl chain ends, and even more preferably at least 95%
allyl chain ends, (for example, at least 95%, or at least 97%, or
at least 98%); ii) a number average molecular weight (Mn) of from
about 500 to about 20,000 g/mol, as measured by .sup.1H NMR,
assuming one olefin unsaturation per chain (for example, from about
500 to about 15,000 g/mol, or from about 700 to about 10,000 g/mol,
or from 800 to about 8,000 g/mol, or from about 900 to about 7,000
g/mol, or from about 1000 to about 6,000 g/mol, or from about 1,000
to about 5,000); iii) an isobutyl chain end to allylic vinyl group
ratio of 0.7:1 to 1.4:1.0; iv) less than 1400 ppm aluminum (for
example, less than 1200 ppm, or less than 1000 ppm, or less than
500 ppm, or less than 100 ppm).
In another embodiment, one or more of the R.sub.1, R.sub.7 and
R.sub.9 groups is independently selected from the group consisting
of propylene copolymers having an Mn of 300 to 30,000 g/mol as
measured by .sup.1H NMR and assuming one olefin unsaturation per
chain (for example, from about 400 to about 20,000 g/mol, or from
about 500 to about 15,000 g/mol, or from about 600 to about 12,000
g/mol, or from about 800 to about 10,000 g/mol, or from about 900
to about 8,000 g/mol, or from about 900 to about 7,000 g/mol),
including from about 10 to about 90 mol % propylene (for example,
15 to 85 mol %, or 20 to 80 mol %, or 30 to 75 mol %, or 50 to 90
mol %) and 10 to 90 mol % (for example, 85 to 15 mol %, or 20 to 80
mol %, or 25 to 70 mol %, or 10 to 50 mol %) of one or more
alpha-olefin comonomers (for example, ethylene, butene, hexene, or
octene, and preferably ethylene), wherein the polymer has at least
70% allyl chain ends, preferably at least 80% allyl chain ends,
more preferably at least 85% allyl chain ends, even more preferably
at least 90% allyl chain ends, and even more preferably at least
95% allyl chain ends.
Alternatively, the polymer or copolymer has at least 80% isobutyl
chain ends (based upon the sum of isobutyl and n-propyl saturated
chain ends), or at least 85% isobutyl chain ends, or at least 90%
isobutyl chain ends. Alternately, the polymer has an isobutyl chain
end to allylic vinyl group ratio of 0.7:1 to 1.3:1.0, or 0.8:1 to
1.40:1.0, or 0.9:1.0 to 1.1:1.0.
In another embodiment, one or more of the R.sub.1, R.sub.7 and
R.sub.9 groups is independently selected from the group consisting
of propylene polymers, comprising more than 90 mol % propylene (for
example, 95 to 99 mol %, or 98 to 9 mol %) and less than 10 mol %
ethylene (for example, 1 to 4 mol %, or 1 to 2 mol %), wherein the
polymer has:
at least 93% allyl chain ends (or at least 95%, or at least 97%, or
at least 98%);
a number average molecular weight (Mn) of about 400 to about 30,000
g/mol, as measured by .sup.1H NMR and assuming one olefin
unsaturation per chain (for example, 500 to 20,000 g/mol, or 600 to
15,000 g/mol, or 700 to 10,000 g/mol, or 800 to 9,000 g/mol, or 900
to 8,000 g/mol, or 1000 to 6,000 g/mol);
an isobutyl chain end to allylic vinyl group ratio of 0.8:1 to
1.35:1.0, and
less than 1400 ppm aluminum, (for example, less than 1200 ppm, or
less than 1000 ppm, or less than 500 ppm, or less than 100
ppm).
In another embodiment, one or more of the R.sub.1, R.sub.7 and
R.sub.9 groups is independently selected from the group consisting
of propylene polymers comprising:
at least 50 (for example, 60 to 90, or 70 to 90) mol % propylene
and from 10 to 50 (for example, 10 to 40, or 10 to 30) mol %
ethylene, wherein the polymer has:
at least 90% allyl chain ends (or at least 91%, or at least 93%, or
at least 95%, or at least 98%);
an Mn of about 150 to about 20,000 g/mol, as measured by .sup.1H
NMR and assuming one olefin unsaturation per chain (for example,
200 to 15,000 g/mol, or 250 to 15,000 g/mol, or 300 to 10,000
g/mol, or 400 to 9,500 g/mol, or 500 to 9,000 g/mol, or 750 to
9,000 g/mol); and
an isobutyl chain end to allylic vinyl group ratio of 0.8:1 to
1.3:1.0, wherein monomers having four or more carbon atoms are
present at from 0 to 3 mol % (for example, at less than 1 mol %, or
less than 0.5 mol %, or at 0 mol %).
In another embodiment, one or more of the R.sub.1, R.sub.7 and
R.sub.9 groups is independently selected from the group consisting
of propylene polymers comprising:
at least 50 (or at least 60, or 70 to 99.5, or 80 to 99, or 90 to
98.5) mol % propylene, from 0.1 to 45 (for example, at least 35, or
0.5 to 30, or 1 to 20, or 1.5 to 10) mol % ethylene, and from 0.1
to 5 (or 0.5 to 3, or 0.5 to 1) mol % C.sub.4 to C.sub.12 olefin
(such as butene, hexene or octene, preferably butene), wherein the
polymer has:
at least 90% allyl chain ends (or at least 91%, or at least 93%, or
at least 95%, or at least 98%);
a number average molecular weight (Mn) of about 150 to about 15,000
g/mol, as measured by .sup.1H NMR and assuming one olefin
unsaturation per chain (for example, 200 to 12,000 g/mol, or 250 to
10,000 g/mol, or 300 to 10,000 g/mol, or 400 to 9500 g/mol, or 500
to 9,000 g/mol, or 750 to 9,000 g/mol); and
an isobutyl chain end to allylic vinyl group ratio of 0.8:1 to
1.35:1.0.
In another embodiment, one or more of the R.sub.1, R.sub.7 and
R.sub.9 groups is independently selected from the group consisting
of propylene polymers comprising:
at least 50 (or at least 60, or 70 to 99.5, or 80 to 99, or 90 to
98.5) mol % propylene, from 0.1 to 45 (for example, at least 35, or
0.5 to 30, or 1 to 20, or 1.5 to 10) mol % ethylene, and from 0.1
to 5 (or 0.5 to 3, or 0.5 to 1) mol % diene (such as C.sub.4 to
C.sub.12 alpha-omega dienes (such as butadiene, hexadiene,
octadiene), norbornene, ethylidene norbornene, vinylnorbornene,
norbornadiene, and dicyclopentadiene), wherein the polymer has:
at least 90% allyl chain ends (or at least 91%, or at least 93%, or
at least 95%, or at least 98%);
a number average molecular weight (Mn) of about 150 to about 20,000
g/mol, as measured by .sup.1H NMR and assuming one olefin
unsaturation per chain (for example, 200 to 15,000 g/mol, or 250 to
12,000 g/mol, or 300 to 10,000 g/mol, or 400 to 9,500 g/mol, or 500
to 9,000 g/mol, or 750 to 9,000 g/mol); and
an isobutyl chain end to allylic vinyl group ratio of 0.7:1 to
1.35:1.0.
Any of the propylene polymers prepared herein can have less than
1400 ppm aluminum, or less than 1000 ppm aluminum, or less than 500
ppm aluminum, or less than 100 ppm aluminum, or less than 50 ppm
aluminum, or less than 20 ppm aluminum, or less than 5 ppm
aluminum.
The terminal allylic vinyl functionality in the PP or EP described
above can be initially prepared by metallocene-catalyzed
polymerization of propylene, or a mixture of ethylene and
propylene, to produce polypropylenes or ethylene-propylene
copolymers terminated with a high vinyl group content in the chain
end. See Scheme 1 below. Such techniques for preparation of
terminal allylic vinyl PP or EP are described in patent application
publications US20090318644, US20090318646, WO20091555471,
WO20091555472 by Brant et al., the disclosure each of which is
incorporated herein by reference in its entirety.
##STR00012##
The terminal vinyl functionality (an alpha-olefin) in these
polypropylenes can undergo cross metathesis reaction with a wide
variety of vinyl compounds bearing polar functional groups (e.g.,
acrylic acid, methacrylic acid, methyl acrylate, methyl
methacrylate, acrylonitrile, etc.) in the presence of a suitable
olefin cross metathesis catalyst such as, but not limited to,
ruthenium- or molybdenum-based carbene complexes to afford the
corresponding cross-metathesized polypropylene derivatives
functionalized with polar functionalities in the chain end.
As an illustration, a selective cross metathesis reaction between
two olefinically unsaturated vinyl type compounds (for example,
R--CH.dbd.CH.sub.2 and X--CH.dbd.CH.sub.2, where R is an alkyl,
aryl, alkylaryl, arylalkyl or polyolefin group and X is a polar
functional group such as carboxylic acid, ester, amide, nitrile or
ether) will lead to the generation of ethylene (a by-product) and
predominantly a mixture of cis- and trans-internal olefin products
as represented by the chemical formula R--CH.dbd.CH--X that
preserves a single olefinic (C.dbd.C bond) unsaturation (Scheme
2).
##STR00013##
Examples of the chemical transformations involved in the
functionalization of vinyl-terminated polypropylenes (bearing an
allylic group, --CH.sub.2--CH.dbd.CH.sub.2 in the polymer chain
end) by cross metathesis reaction with several representative polar
vinyl compounds (e.g., acrylic acid, methyl acrylate) are
illustrated in Scheme 3. This reaction scheme is described, for
purpose of illustration, in two patent application publications
US20090318647 and WO2009155517 by Hagadorn et al., the disclosure
of each of which is incorporated herein by reference in its
entirety.
##STR00014##
Using the synthesis of high vinyl-terminated polypropylenes by a
metallocene process and their subsequent functionalization by cross
metathesis reactions (as described in the above referenced patent
applications), polymers terminally functionalized with carboxylic
acid-polyamine are developed as antifoulants in the present
application. For example, the carbon-carbon double bond in the
polypropylene acrylic acid (or ester) cross metathesis products (as
shown on the right-hand sides in Scheme 3) can be first saturated
by a selective, catalytic hydrogenation step employing a catalyst
such as palladium supported on activated carbon and a suitable
inert solvent (e.g., cyclohexane) conducted under moderate hydrogen
pressure at room temperature for several hours (Scheme 4). Under
these reaction conditions the polar functional groups (carboxylic
acid or ester) are unaffected (which can be confirmed by .sup.1H
NMR characterization and elemental analyses), and can be further
used for reacting with a polyamine.
##STR00015##
The next stage for preparing the antifoulants of the presently
disclosed subject matter involves reacting the terminally
acyl-functionalized polymer, e.g., the above-discussed
polypropylene butanoic acid or ester (or the compounds before
hydrogenation, i.e., polypropylene acrylic methyl ether or
polypropylene acrylic acid), with polyamines (PAM) to provide an
antifoulant additive consisting of a polymer terminally
functionalized with polyamine with an amide linker group, e.g.,
PP-Acid-PAM amide, as depicted in Scheme 5.
##STR00016##
Examples of the polyamines suitable for use in the presently
disclosed subject matter include, but are not limited to,
polyethyleneamines with general molecular formula
H.sub.2N(CH.sub.2CH.sub.2NH).sub.mH (where m=1, 2, 3, . . . ) such
as ethylenediamine, diethylenetriamine (DETA), triethylenetetramine
(TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine
(PEHA), hexaethyleneheptamine (HEHA), or higher molecular weight
species, such as heavy polyamines or polyamine bottoms having
greater number of nitrogens per molecule. In one embodiment, the
polyamine can be "Heavy Polyamine X" or HPA-X available from Dow
Chemical (Midland, Mich.). Other commercially available lower or
higher polyamines with linear, branched, cyclic or heterocyclic
structures can also be conveniently used. As understood by those
skilled in the art, these polyamines can be mixtures of compounds
comprised of molecules with a distribution of chain lengths,
different level and type of amine (primary, secondary, and
tertiary) functional groups, and varying degree of linear, branched
and cyclic structures. This information is illustrated for
tetraethylenepentamine below. As the molecular weight of polyamines
increases, the number of possible isomers increases as well.
##STR00017##
In some embodiments, the mole ratio between the polymer base unit
R.sub.11 and polyamine in the antifoulants prepared according to
the above techniques ranges from about 5:1 to about 1:1, or from
about 3:1 to about 1:1. By using polyamines containing more than
one reactive amine groups per molecule, the polyamines can react
with more than one molecule of terminally acyl-functionalized
polymer under suitable conditions.
Furthermore, by selecting vinyl-terminated polypropylenes of
different molecular weights (M.sub.n) and molecular weight
distribution (MWD) and polyamines of different chain lengths and
molecular composition (e.g., ethylene amine oligomers with a
general formula of H.sub.2N(CH.sub.2CH.sub.2NH).sub.mH or propylene
amine oligomers with a formula of
H.sub.2N(CH.sub.2CH.sub.2CH.sub.2NH).sub.mH (where m=1, 2, 3, . . .
), these polypropylene-polyamine amide based dispersants can be
molecularly designed to have different amount of basic nitrogen
contents and hence varying degrees of dispersancy. Similar to the
well-known polyisobutylene-succinic anhydride-polyamine family of
dispersant additives, and not being bound by any particular theory,
the polar head groups (i.e., polyamine) in the polypropylene
carboxylic acid-polyamine amides are believed to be largely
responsible for the ability of the antifoulants to disperse
particulates in crude oils and these polyamines possess strongly
basic amine groups for such effective dispersion. Other factors
affecting the fouling prevention performance include, but are not
limited to the type of polymer, molecular weights and distribution,
type of polyamine used and amine group distribution in the
composition of the resulting dispersant.
The above-described method for preparing an antifoulant by the
hydrogenation of the terminally acrylic-functionalized polymer
followed by amination is also encompassed in the currently
disclosed subject matter.
The additives of the presently disclosed subject matter can be used
in compositions that reduce fouling, including particulate-induced
fouling. In addition to the additives of the presently disclosed
subject matter, the compositions can further contain a hydrophobic
oil solubilizer for the additive and/or a dispersant for the
additive. Suitable solubilizers can include, for example,
surfactants, carboxylic acid solubilizers, such as the
nitrogen-containing phosphorous-free carboxylic solubilizers
disclosed in U.S. Pat. No. 4,368,133, hereby incorporated by
reference in its entirety. Also as disclosed in U.S. Pat. No.
4,368,133, hereby incorporated by reference in its entirety,
surfactants that can be included in compositions of the presently
disclosed subject matter can include, for example, cationic,
anionic, nonionic or amphoteric type of surfactant. See, for
example, McCutcheon's "Detergents and Emulsifiers", 1978, North
American Edition, published by McCutcheon's Division, MC Publishing
Corporation, Glen Rock, N.J., U.S.A., including pages 17-33, which
is hereby incorporated by reference in its entirety.
The compositions of the presently disclosed subject matter can
further include a boronating agent. The boronating agent can be any
one or more compounds selected from boric acid, an ortho-borate, or
a meta-borate, for example, boric acid, trimethyl metaborate
(trimethoxyboroxine), triethyl metaborate, tributyl metaborate,
trimethyl borate, triethylborate, triisopropyl borate
(triisopropoxyborane), tributyl borate (tributoxyborane) and
tri-t-butyl borate. Other boronating agents can be used, such as
those disclosed in co-pending application U.S. Ser. No. 12/533,465,
filed Jul. 31, 2009, and published as U.S. 2010/0038290, which is
hereby incorporated by reference in its entirety.
The compositions of the presently disclosed subject matter can
further include, for example, viscosity index improvers,
anti-foamants, antiwear agents, demulsifiers, anti-oxidants, and
other corrosion inhibitors.
Furthermore, the additives or compositions of the presently
disclosed subject matter can be added with other compatible
components that address other problems that can present themselves
in an oil refining process known to one of ordinary skill in the
art.
Uses of the Additives and Compositions of the Presently Disclosed
Subject Matter in a Refinery Process
Another aspect of the presently disclosed subject matter provides a
system for refining hydrocarbons that includes at least one crude
hydrocarbon refinery component, in which the crude hydrocarbon
refinery component includes an additive selected from any one of
the additives described herein. The crude hydrocarbon refining
component can be selected from a heat exchanger, a furnace, a crude
preheater, a coker preheater, a FCC slurry bottom, a debutanizer
exchanger, a debutanizer tower, a feed/effluent exchanger, a
furnace air preheater, a flare compressor component, a steam
cracker, a steam reformer, a distillation column, a fractionation
column, a scrubber, a reactor, a liquid-jacketed tank, a pipestill,
a coker, and a visbreaker. In one preferred embodiment, the crude
hydrocarbon refining component is a heat exchanger (e.g., a crude
pre-heat train heat exchanger).
The additives of the presently disclosed subject matter are
generally soluble in a typical hydrocarbon refinery stream and can
thus be added directly to the process stream, alone or in
combination with other additives that either reduce fouling or
improve some other process parameter.
The additives can be introduced, for example, upstream from the
particular crude hydrocarbon refinery component(s) (e.g., a heat
exchanger) in which it is desired to prevent fouling (e.g.
particulate-induced fouling). Alternatively, the additive can be
added to the crude oil prior to being introduced to the refining
process, or at the very beginning of the refining process.
It is noted that water can have a negative impact on
boron-containing additives. Accordingly, it is advisable to add
boron-containing additives at process locations that have a minimal
amount of water.
While not limited thereto, the additives of the presently disclosed
subject matter are particularly suitable in reducing or preventing
particulate-induced fouling. Thus one aspect of the presently
disclosed subject matter provides a method of reducing and/or
preventing, in particular, particulate-induced fouling that
includes adding at least one additive of the presently disclosed
subject matter to a process stream that is known, or believed to
contribute to, particulate-induced fouling. To facilitate
determination of proper injection points, measurements can be taken
to ascertain the particulate level in the process stream. Thus, one
embodiment of the presently disclosed subject matter includes
identifying particular areas of a refining process that have
relatively high particulate levels, and adding any one of the
additives of the presently disclosed subject matter in close
proximity to these areas (e.g., just upstream to the area
identified as having high particulate levels).
In one embodiment of the presently disclosed subject matter, a
method to reduce fouling is provided comprising adding any one of
the above-mentioned antifouling additives or compositions to a
crude hydrocarbon refinery component that is in fluid communication
with a process stream that contains, at least 25 or 50 wppm of
particulates, including organic and inorganic particulates. In
another embodiment of the presently disclosed subject matter, a
method to reduce fouling is provided comprising adding any one of
the above-mentioned antifouling additives or compositions to a
crude hydrocarbon refinery component that is in fluid communication
with a process stream. In another embodiment of the presently
disclosed subject matter, a method to reduce fouling is provided
comprising adding any one of the above-mentioned additives to a
crude hydrocarbon refinery component that is in fluid communication
with a process stream that contains at least 250 wppm (or 1000
wppm, or 10,000 wppm) of particulates, including organic and
inorganic particulates, as defined above.
In one embodiment of the presently disclosed subject matter, the
additives or compositions of the presently disclosed subject matter
are added to selected crude oil process streams known to contain,
or possibly contain, problematic amounts of organic or inorganic
particulate matter (e.g. 1-10,000 wppm), such as inorganic salts.
Accordingly, the additives of the presently disclosed subject
matter can be introduced far upstream, where the stream is
relatively unrefined (e.g. the refinery crude pre-heat train). The
additives can be also added, for example, after the desalter to
counteract the effects of incomplete salt removal or to the bottoms
exit stream from the fractionation column to counteract the high
temperatures that are conducive to fouling.
Other applications and uses of the antifoulants and antifoulant
compositions of the presently disclosed subject matter are
contemplated. For example and not limitation, the antifoulants and
antifoulant compositions can be used as dispersant for treating oil
spill, additives in fuel compositions, lubricating oil dispersants
for dispersion of sludge/soot/particulate in lubricating oil, fuel
additives for cleaning up or preventing deposits in fuel storage
tank and fuel injection systems.
FIG. 1 demonstrates possible additive injection points within the
refinery crude pre-heat train for the additives of the presently
disclosed subject matter, wherein the numbered circles represent
heat exchangers. As shown in FIG. 1, the additives can be
introduced in crude storage tanks and at several locations in the
preheat train. This includes at the crude charge pump (at the very
beginning of the crude pre-heat train), and/or before and after the
desalter, and/or to the bottoms stream from a flash drum.
The total amount of additive to be added to the process stream can
be determined by a person of ordinary skill in the art. In one
embodiment, up to about 1000 wppm of additive is added to the
process stream. For example, the additive can be added such that
its concentration, upon addition, is about 50 ppm, 250 ppm or 500
ppm. More or less additive can be added depending on, for example,
the amount of particulate in the stream, the .DELTA.T associated
with the particular process and the degree of fouling reduction
desired in view of the cost of the additive.
The additives or compositions of the presently disclosed subject
matter can be added in a solid (e.g., powder or granules) or liquid
form directly to the process stream. As mentioned above, the
additives or compositions can be added alone, or combined with
other components to form a composition for reducing fouling (e.g.,
particulate-induced fouling). Any suitable technique can be used
for adding the additive to the process stream, as known by a person
of ordinary skill in the art in view of the process to which it is
employed. As a non-limiting example, the additives or compositions
can be introduced via injection that allows for sufficient mixing
of the additive and the process stream.
EXAMPLES
The presently disclosed subject matter is further described by
means of the examples, presented below. The use of such examples is
illustrative only and in no way limits the scope and meaning of the
disclosed subject matter or of any exemplified term. Likewise, the
presently disclosed subject matter is not limited to any particular
preferred embodiments described herein. Indeed, many modifications
and variations of the presently disclosed subject matter will be
apparent to those skilled in the art upon reading this
specification. The presently disclosed subject matter is therefore
to be limited only by the terms of the appended claims along with
the full scope of equivalents to which the claims are entitled.
Example 1
Preparation of Antifoulants of the Presently Disclosed Subject
Matter
A. General Procedure for Hydrogenation of Polypropylene Acrylic
Acid or Methyl Ester to Polypropylene Butanoic Acid or Methyl
Ester
Example 1.1
Hydrogenation of Polypropylene Acrylic Acid to Polypropylene
Butanoic Acid
The following procedure was used to carry out the hydrogenation of
polypropylene acrylic acid (PPAA). To a 300 cc autoclave equipped
for stirring and gas flow through 6.08 g of a PPAA polymer
pre-mixed with 100 ml of cyclohexane solvent was added along with
0.5 g of Pd on carbon catalyst (5% Pd). The system was then flushed
with nitrogen to remove air. Finally the autoclave was charged to
200 psig with hydrogen and mixed at 1300 rpm for six hours at room
temperature. The autoclave was vented and the reacted mixture was
then filtered through Celite.RTM. to remove the catalyst. The
mixture was then concentrated on a rotary evaporator to remove the
cyclohexane solvent and the hydrogenated clear polymer product was
recovered. Complete hydrogenation was confirmed by proton NMR. This
sample has a carboxylic acid content of 0.972 mmol/g and a
number-averaged molecular weight (by .sup.1H NMR) of 976 g/mol (MO,
assuming one carboxylic acid group per polymer chain.
Example 1.2
Hydrogenation of Polypropylene Acrylic Acid to Polypropylene
Butanoic Acid
To a 300 cc autoclave equipped for stirring and gas flow through
22.6 g of a PPAA polymer pre-mixed with 100 ml of cyclohexane
solvent was added along with 0.79 g of Pd on carbon catalyst (5%
Pd). The system was then flushed with nitrogen to remove air.
Finally the autoclave was charged to 200 psig with hydrogen and
mixed at 1300 rpm for six hours at room temperature. The autoclave
was vented and the reacted mixture was then filtered through
Celite.RTM. to remove the catalyst. The mixture was then was then
concentrated on a rotary evaporator to remove the cyclohexane
solvent and the hydrogenated clear polymer product was recovered.
Complete hydrogenation was confirmed by proton NMR. This sample has
a carboxylic acid content of 0.375 mmol/g and a number-averaged
molecular weight (by .sup.1H NMR) of 2154 g/mol (Mn) assuming one
carboxylic acid group per polymer chain.
Example 1.3
Hydrogenation of Polypropylene Acrylic Acid to Polypropylene
Butanoic Acid
A viscous PPAA polymer (6.0 g) was heated to 150.degree. C. and
pre-mixed at room temperature with 50 ml of cyclohexane before
adding to the autoclave. An additional 50 ml of cyclohexane was
added and then the mixture was hydrogenated as in Example 1.1.
Complete hydrogenation and the structure of the product was
confirmed by proton NMR. This sample has a carboxylic acid content
of 0.166 mmol/g and a number-averaged molecular weight (by .sup.1H
NMR) of 4876 g/mol (Mn) assuming one carboxylic acid group per
polymer chain.
Example 1.4
Hydrogenation of Polypropylene Acrylic Methyl Ester Polymer to
Polypropylene Butanoic Methyl Ester
To a 300 cc autoclave equipped for stirring and gas flow through
15.56 g of a polypropylene acrylic methyl ester pre-mixed with 100
ml of cyclohexane solvent was added along with 1.02 g of Pd on
carbon catalyst (5% Pd). The mixture was hydrogenated as in Example
1.1 at 450 psig of hydrogen pressure for 7 hours at room
temperature. Complete hydrogenation and the structure of the
product was confirmed by proton NMR. This sample has a carboxylic
ester content of 0.525 mmol/g and a number-averaged molecular
weight (by .sup.1H NMR) of 2408 g/mol (M.sub.n) assuming one
carboxylic ester group per polymer chain.
B. General Procedure for Condensation of Polypropylene Butanoic
Acid with Polyamine to Prepare Polypropylene Carboxylic
Acid-Polyamine Amide
Example 1.5
A mixture of polypropylene butanoic acid from Example 1.1 in the
hydrogenation experiment (3.00 g, 2.916 mmol of CO.sub.2H group),
tetraethylenepentamine (0.45 g, 2.38 mmol, 0.82 equiv.) and xylenes
(50 ml) was heated at reflux (oil bath temperature 175.degree. C.)
under a nitrogen atmosphere for 72 hr. A Dean-Stark trap was used
to collect any water formed in the condensation reaction. After the
reaction was completed, the mixture was allowed to cool to room
temperature, and excess xylenes was removed initially on a rotary
evaporator followed by heating under high vacuum to afford a light
brown oil (Additive A, 3.20 g) as crude product. The structure and
purity of the crude product was established by .sup.1H and .sup.13C
NMR (CDCl.sub.3, 400 and 100 MHz, respectively), which confirmed
complete conversion of the carboxylic acid group to the
corresponding amide linkage. This sample has a nitrogen content of
4.34% based on elemental analysis.
Example 1.6
A mixture of polypropylene butanoic acid from Example 1.2 in the
hydrogenation experiment (6.00 g, 2.25 mmol of CO.sub.2H group),
tetraethylenepentamine (0.34 g, 1.80 mmol, 0.80 equiv.) and xylenes
(50 ml) was heated at reflux (oil bath temperature 175.degree. C.)
under a nitrogen atmosphere for 72 hr. A Dean-Stark trap was used
to collect any water formed in the condensation reaction. After the
reaction was completed, the mixture was allowed to cool to room
temperature, and excess xylenes was removed initially on a rotary
evaporator followed by heating under high vacuum to afford a light
brown viscous oil (Additive B, 6.16 g) as crude product. The
structure and purity of the crude product was established by
.sup.1H and .sup.13C NMR which confirmed conversion of the
carboxylic acid group to the corresponding amide linkage. This
sample has a nitrogen content of 1.91% based on elemental
analysis.
Example 2
Fouling Reduction Measured in the Alcor HLPS (Hot Liquid Process
Simulator)
FIG. 2 depicts an Alcor HLPS (Hot Liquid Process Simulator) testing
apparatus used to measure the impact of addition of particulates to
a crude oil on fouling and the impact the addition of an additive
of the presently disclosed subject matter has on the mitigation of
fouling. The testing arrangement includes a reservoir 10 containing
a feed supply of crude oil. The feed supply of crude oil can
contain a base crude oil containing a whole crude or a blended
crude containing two or more crude oils. The feed supply is heated
to a temperature of approximately 150.degree. C./302.degree. F. and
then fed into a shell 11 containing a vertically oriented heated
rod 12. The heated rod 12 is formed from carbon-steel (1018). The
heated rod 12 simulates a tube in a heat exchanger. The heated rod
12 is electrically heated to a surface temperature of 370.degree.
C./698.degree. F. or 400.degree. C./752.degree. F. and maintained
at such temperature during the trial. The feed supply is pumped
across the heated rod 12 at a flow rate of approximately 3.0
mL/minute. The spent feed supply is collected in the top section of
the reservoir 10. The spent feed supply is separated from the
untreated feed supply oil by a sealed piston, thereby allowing for
once-through operation. The system is pressurized with nitrogen
(400-500 psig) to ensure gases remain dissolved in the oil during
the test. Thermocouple readings are recorded over the course of
simulated test runs for the bulk fluid inlet and outlet
temperatures and for surface of the rod 12.
FIG. 3 illustrates the impact of fouling of a refinery component
over 180 minutes at a rod surface temperature of 370.degree. C. Two
blends were tested in the Alcor unit: a crude oil control (control
blend 9) containing added rust (iron oxide) particles (200 wppm) in
the absence of an additive, and the same stream with the addition
of 50 wppm of a PP-CA-PAM additive, i.e., Additive A as prepared in
Example 1.5, above. As FIG. 3 demonstrates, the reduction in the
outlet temperature over time (due to fouling) is less for the
process blend containing 50 wppm of additive as compared to the
crude oil control without the additive. This indicates that the
PP-CA-PAM is effective for reducing fouling of a heat
exchanger.
FIG. 4 demonstrates the results of the Alcor test at a rod surface
temperature of 370.degree. C., using another crude oil control
(control blend 12) and the control with the addition of 50 wppm of
another PP-CA-PAM additive, i.e., Additive B as prepared in Example
1.6, above. As FIG. 4 indicates, this PP-CA-PAM was also effective
for reducing fouling.
The presently disclosed subject matter is not to be limited in
scope by the specific embodiments described herein. Indeed, various
modifications of the disclosed subject matter in addition to those
described herein will become apparent to those skilled in the art
from the foregoing description and the accompanying figures. Such
modifications are intended to fall within the scope of the appended
claims.
It is further to be understood that all values are approximate, and
are provided for description.
Patents, patent applications, publications, product descriptions,
and protocols are cited throughout this application, the disclosure
of each of which is incorporated herein by reference in its
entirety for all purposes.
* * * * *